FIG 4.
C. neoformans Ric8 protein regulates the pheromone response and mating. (A) The ric8, ric8 RIC8 complemented, ric8 gpa1, ric8 GPA1Q284L, gpa1, gpa2, gpa3, and wild-type strains were streaked in proximity to the MATa crg1 strain on filament agar, and the plates were incubated in the dark at room temperature for 3 days. Only the ric8 mutant showed stubby conjugation tube-like structures, and the paired crg1 strain showed abundant conjugation tubes. (B) The same strains were also mixed with KN99a by patching onto V8 agar and incubated for 7 days. The cross with the ric8 mutant resulted in attenuated formation of dikaryotic filaments and basidiospores, similar to that of gpa1. The attenuation was most severe in the ric8 gpa1 double-mutant strain. The assays were repeated multiple times, and representative images are shown.